


In which Jean didn’t know Eren was a girl until he was told so (alternatively, Marco’s a fucking saint)

by pandaspots



Category: Shingeki no Kyojin | Attack on Titan
Genre: F/M, Marco how the fuck you put up with his stupid ass all this time, Originally Posted on Tumblr, contains genderbent Eren, for an A+ student you're pretty stupid jean, this is pure crack and it was written at 2AM
Language: English
Status: Completed
Published: 2013-11-26
Updated: 2013-11-26
Packaged: 2018-01-02 16:25:24
Rating: Mature
Warnings: Creator Chose Not To Use Archive Warnings
Chapters: 1
Words: 4,263
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/1059008
Author URL: https://archiveofourown.org/users/pandaspots/pseuds/pandaspots
Summary: <blockquote class="userstuff">
              <p>Also named in which Jean finds his childhood rival a hot piece of ass and is conflicted, but not enough not to do her when she offers.</p>
<p>Eren's a girl, Jean is genderblind, Marco is Freckled Jesus and Dr. Jäger is beyond amused.</p>
            </blockquote>





	In which Jean didn’t know Eren was a girl until he was told so (alternatively, Marco’s a fucking saint)

**Author's Note:**

> So this was written at 2AM of one of my beautiful insomnia crisis. It's based on a real story, featuring me and one of my childhood friends, who was particularly distressed to find out at our english course Halloween party, that I was a girl and THAT was why throughout our ENTIRE CHILDHOOD I wore frilly flowery dresses.  
> (we didn't bang afterwards because unlike Eren i was a gross greasy goth at 16 and he's gay)

So they were fighting again. Jean had Eren pinned down _again_. Eren kneed his spleen _again_. Jean sputtered and tried to grab her hair _again_. She kicked him in the stomach _again_. They did that pretty much every week. Only today…  
"Ouch!"  
Jean was not entirely sure what he did, but Eren looked terrified and she was definitely crying, arms wrapped around her chest. He swiftly ignored that gnawing feeling that he cheated somehow to feel proud that he finally managed to beat Eren, ending the eleven year old streak of ties.  
He only felt anything, though, until Eren recovered enough to kick him in the balls. So much for ending the ties streak.  
He was never again able to do whatever he did again, because suddenly Eren’s main focus of defense was on her chest.  
"You really gotta stop fighting with Eren for every little shit you two disagree on, Jean." Marco chastised him, bandaging his arm where Eren managed to scrape him on the pavement. "You’re sixteen, act like it, man."  
"She doesn’t act like it, why should I?" In retrospect, that was really childish of him. He didn’t care. "Marco, you’re supposed to be on _my_ side here!"  
"I am, I really am, but have you thought about Eren? She’s in _pain_ , and you go teasing her about _her hair being a mess_."  
"Wait, why would Eren be in pain?"  
Marco just shot him a disbelieving look.

Eren _cheated_. He couldn’t say how, but he knew _she cheated_.  
He couldn’t have _lost_ to her, now, could he.  
She kept staring down at him, only a narrow patch of green showing, a very creepy smile on her face.  
"You lose, horseface." She laughed, but he could see that she strained the laugh a bit at the end, hand covering the lower half of her stomach, her creepy grin contorting slightly into a grimace.  
She kicked his leg, for good measure it seemed.  
" _What the fuck is going on with Eren?_ " He asked Marco, who sighed the sigh of the saints.

Right on cue, the next month, Eren managed to beat his ass again. It was like she has been through real pain and nothing he could do ( _including_ pulling her hair) got through whatever she had going on.  
She was straddling him, holding him by his shirt, green-blue eyes glinting in pure anger, fist up ready to break his nose, and then it was all gone. The anger vaporized as she turned redder and redder. He had no clue what just happened, but he took the chance to wrestle her down and pinned her hands to the ground, straddling her, and her eyes went wide, her breath hitching and he thought he saw something, lowering his guard for a split second…  
And then she threw him off and did something he never saw her doing until today. She ran away. And he noticed he had something going on downstairs he couldn’t really justify.  
"I don’t know what’s going on, really." He told Marco, after finishing relaying the tale, and his best friend just hid his face in a pillow and screamed. "What? Dude, you gotta stop with these things, I don’t know what you’re going on about!"  
"Jean, you know Ymir?"  
"Yeah, the lesbian chick who’s all up Christa’s business? What does she had to do with it?" He was honestly confused.  
"Nothing, really, just testing. Okay now, you remember sex ed?"  
"Yeah, I remember it was lame."  
"Oh, God, help me." Marco whined, and hoped this would qualify him for fucking sainthood. "You remember the teacher talking about girls and periods?"  
"Yeah, man, that was _gross_. What does that have to do with Eren being weird?"  
 _Yeah_ , Marco though. _Definitely qualifying for sainthood in LIFE._  
"I don’t know how else to break it to you. Eren’s a girl."  
"No shit, Sherlock."  
"Jean, are you being serious. _Eren. Is. A. Girl._ "  
"Yeah but—" And then it clicked. " _DO YOU MEAN I PUNCHED HER BOOBS?_ " He yelled, horrorized.  
" _I THOUGHT YOU WERE GOING TO REALIZE THAT WELL INTO YOUR THIRTIES._ " Marco screamed right back, torn between crying and laughing. "But man. _Seriously_. You were the first of us to ever touch a girl’s boobs and you didn’t even realize, I think Reiner’s gonna have a cow when I tell him."  
"Shut up, man, I’ve been getting into fights with Eren for long enough. She’s got a mean punch, do you think I could tell the difference between her and Bertl? Because I can’t. You can say she beat the awareness out of me."  
"Not entirely or you wouldn’t have popped a boner." Marco mumbled.  
"Dude, I can’t even justify that. I don’t even know what was going on. She was glaring at me with those eyes—"  
"What the hell man."  
"What?" Jean asked, defensively.  
"It’s like the third time today you mention her eyes. I know they’re this weird green, but man."  
He threw a pillow at Marco’s face.  
That night, Jean dreamed of green-blue eyes and hands on his chest and woke up with a mess on his bedsheets.  
He thanked God it was the first day of summer break, because otherwise he would never gather the nerve to look in Eren’s eyes again.  
The prospective of looking in her eyes again didn’t make it any less weird.

Reiner’s parents had left him alone in the house for three days. He had promptly called in a pool party. Because what else would you do in a huge house with a pool with the entire summer ahead of you and three days with no parental supervision?  
It was a small thing, not big enough to be an actual party, but a party nonetheless, with loud music, lots of soda, and girls in swimsuits.  
Jean tried not to think a lot about the last part.  
It was hard, because suddenly he was noticing just how long Eren’s legs were.  
"Tone the staring down or you’re gonna need to inaugurate the pool, man." Reiner mocked him.  
"Did you know Eren was this pretty?" He asked, not actually believing what he was saying.  
"Dude, you were the only one who _didn’t_ know."  
That left Jean with a weird feeling in his stomach.  
He didn’t however, tone down the staring. He went from assessing her legs to checking out her waist, and then thoughts of how well his hands would fit there made him indeed inaugurate the pool. And because Eren was Eren, she jumped right after him, surfacing rather gracelessly, laughing. He figured he never really heard her laugh before. He kept staring. At her shoulders. Her arms when she tied her hair in a loose bun, which exposed her neck for a second before falling apart and Mikasa sighing and having to redo it. Her neck when Mikasa got out of his line of sight, and he could just see it all covered in bite marks. _Whoa man_ , he thought to himself, shuffled awkwardly because the cold water was doing nothing for him anymore and closed his eyes, still with the image of her neck in his mind. He opened his eyes only to look at angry green-blue ones, and for a second he thought he hadn’t opened his eyes until he realized that indeed, Eren was there in front of him, glaring at him something fierce, and she looked really hot when she was about to punch the living daylights out of him.  
"What are you looking at, horseface, lost something?"  
"My mind in those curves." He mumbled, thinking no one had heard it, but it rang really loud on the sudden silence following Eren’s words. He realized then that everyone heard what he said, and braced himself for a punch. He got hit on the face, however Eren’s favourite method of hurting him was exchanged for a far more stinging and weirdly feminine slap.  
In a daze of being weirded out by himself and freaked out his nose was still intact, he pulled himself out and made a beeline to where Reiner had started with the beer.  
Slowly, one by one, they all started to get out of the pool, joining the two boys and talking about anything but the weird display between Jean and Eren, who had yet to start a fight. Eren was wrapped up in a towel, shooting withering glares at Jean’s direction, finishing one bottle of beer in one go, glaring even more at Berthold when he tried to tell her to slow down. Poor guy, soft as he was, hid behind Annie, and Eren grabbed a second bottle.  
Jean barely finished his one bottle and Eren already reached for her third bottle, Mikasa trying to slow her down to no avail.  
Someone had the unfortunate idea of turning this into an actual teenage party by putting on Far East Movement and that was the excuse he used to scoot away to the corner Eren had taken up residence with her fourth beer of the night. If there was one thing they agreed, was that electronic music sucked.  
It was a tense silence. They drank quietly, until Eren finally dried the bottle and threw it aside with less finality than she probably intended, flopping on her back.  
"You’re an ass." She informed him, and he chuckled. "You are literally the lowest creature God could ever conceive, horseface."  
"That’s rich, coming from an world-class bitch." He shot back.  
"Why do you hate me?" She asked suddenly, and he turned to look at her in surprise. Bad move, Jean realized, as turning around presented him with a view of pretty legs and surprisingly nice boobs.  
"I don’t hate you." He said, trying not to think too much about the wild implications. "Thought _you_ hated _me_." He shot back.  
"I did, at first." She admitted, and he made a point of trying to look away as she sat up, legs spread like a guy’s, only she was a really hot girl and the position and lack of clothes made for something right out of Playboy. "Then it became a habit."  
"Same." He laid down beside her for lack of things to do that didn’t involve outright ogling Eren.  
"Oh no, they didn’t."  
Indeed, Akon was pushing the limits.  
"I’m out of here." She announced, getting up and grabbing another beer.  
"Same." He agreed, partially because hip-hop didn’t suit his fancy, but mostly because he wanted to try and hover around Eren without being beaten bloody.  
He just wanted to follow that hip sway into the sunset, really.  
He was almost in front of Eren’s house when he noticed that.  
"Hey, horseface, what the fuck are you doing here, isn’t your house _three blocks_ back?" Her voice snapped him out of his Eren-induced daze and he nodded dumbly.  
"Making sure you didn’t get jumped or some shit." Jean mumbled and he knew it was bullshit, but he didn’t care.  
She straightened up at that (Jean can’t help but notice her boobs perk up), and stalked right up to him. He thought she was gonna punch his breath out for that. She did do something to his breathing alright, although the feeling of soft, girly lips on his was much more pleasant than a fist to his ribs. They parted lips and he felt Eren’s tongue slipping in to gain the upper hand. Not likely, he thought, kissing back and sliding his hands into her hair, pulling on it a bit, feeling the slight moan she let out.  
"Hey, Jean, wanna fuck?" She asked bluntly, when she shoved him away at a relatively safe distance.  
"I… Uh. What about your dad?" He croaked, mentally kicking himself for not just saying yes and diving headfirst.  
"Conference in Zurich. Won’t be back until the weekend." She leaned in and whispered in his ear, shoving her hands into his shirt.   
He felt like he was sneaking behind someone’s husband.  
"Hey, horseface, yes or no before I change my mind." She started walking away, and looked ready to leave him with a red face and a boner in the middle of the street.  
Jean did what any red-blooded, teenaged, horny male faced with the opportunity to have wild hate(ish)-sex with a hot, willing girl would do. He followed her into the house, throwing Eren onto the nearest flat surface, biting her neck and licking his way up to kiss her mouth, egged on by her moaning and hands on his hips that kept pulling him closer and closer and he really wanted her not to do this because they couldn’t leave clothes strewn across the house, but then she pulled his shirt off and it was _on_.  
"Shit— Eren, I don’t want to do it on the couch." He pulled her off his neck, and he was pretty sure she was trying to eat him, with how hard she was biting his neck.  
"I’d love to do it against the wall, too, but the box of condoms dad gave me is in my bedroom…" She whispered against his skin, and it clicked. It finally clicked that he was going to have sex with Eren, who apparently had grown up from the boyish runt she was into a really really hot girl who apparently was willing to have sex with him against a wall.  
"Are you for real?" He asked disbelieving, and she chuckled.  
"Shut up and follow me, horseface."  
He did, though not keeping his hands to himself and almost tripping the two of them on the stairs, his shorts and her bikini top thrown about as he attempted not to be an irresponsible douche and just do her against the wall.  
But then, it wasn’t like Eren ceased to be her backtalking, annoying self, she just got hotter.  
(Meaning he didn’t want to even begin thinking what the possible child of theirs could even be like lest he lost his boner forever so he just manned up and braved the walk to Eren’s bedroom.)  
He expected to get a good glance at what her bedroom looked like, but he heard her rummaging through something and getting back to pull his swimming trunks down, and he actually moaned at the sudden freedom that gave his dick.  
He saw as she ripped off the condom wrapping and expertly (as if she’s done this before and knowing her, she probably did) putting it on him, and freaking finishing unwrapping it with her mouth.  
Jean didn’t know what to feel; horny as fuck, impressed by her lack of gag reflex or terrified because this meant she probably got more action than he did.  
Anyone who could finish putting on a condom with her mouth had a big history in his book.  
As Eren threw him on her bed and kicked off her last garments, he decided that he didn’t care about her history one bit if it led to awesome sex.  
He wanted to say that he took matters into his own hands and threw the girl on her back and fucked her into the mattress, but all he did was grab her boobs and squeeze as she rode the fuck out of him, her hands on his chest, just like it happened in his dreams.  
But dreams are only nice because they don’t require you to move from sleep paralysis, and so he toppled Eren over, biting hard on her neck and feeling himself go impossibly harder at the sounds of her loud moaning. He never pegged her as a screamer, because he always heard loud girls didn’t make noise in bed but this was way better than his dreams. Specially because she was taunting him.  
"Is that the best you can do, asshat? _My hands_ are better than t—" Anything she could’ve said from the half of her sentences on were just really loud pleasure screaming, and while he was pretty sure he was making a lousy work, he was coming to the conclusion she was a horny drunk.

He woke up the next day with a headache, a sleepy arm, and a dead weight on his chest.  
Of course that was courtesy of the beer, the position he slept in, and Eren.  
Eren also gave Jean a hard-on in the first minutes of being awake. He should have foreseen that, being as hyper as she was on a regular basis, the she would be also a messy sleeper. But in fact, she was clinging to him, nuzzling his chest and generally acting both really cute and really sexy (specially when she actually laid over his chest, a leg between his legs, sleepily kissing his jaw and absent-mindedly running her nails down his stomach).  
Of course, all ruined when she murmured a name that wasn’t his.  
"Levi…"  
It was just like Eren, to be saying someone else’s name.  
"Wake up, _leiderhoser_. You’re crushing my inner organs." And his pride, too, but he thought better not to mention that.  
"Huh? Jean? How the hell are you in my bed?" She asked, sleepily. "Wait no, don’t answer. I’m not functioning yet and I think I’ll remember later." She slipped off him and tried to kick him off the bed. "Get me coffee, dumbass."  
"You’re a spoiled princess, aren’t you." He yawned, but got up anyway, very very naked and remembering he did not plan on sleeping over Reiner’s and therefore would have to put on his swimming trunks (found still in her bedroom) and his shorts (on the stairs). His shirt was nowhere to be found, so he just headed into the kitchen to be shocked with the knowledge that _Dr. Jäger was back and that yesterday was Friday_.  
"Hello, Jean." Eren’s dad said, cheerfully.  
"Uhm. Hello, Dr. Jäger."  
"There are mugs in the counter behind you, hers is the one with pink flowers and she takes her coffee with two spoonfuls of powder milk and one of sugar." The man informed, sipping his own mug of coffee.  
"Thanks."  
He made sure to follow the instructions with military precision. As he was going out of the kitchen to get Eren her coffee, he heard the man say something.  
"Your shirt is folded on the couch."  
He bolted to Eren’s room as fast as he could without sloshing the coffee.  
She was sitting on the bed, her hair pointing to every direction, stretching, stark naked. She didn’t seem the least bit ashamed by Jean’s presence in the room. She did however, seem every bit awake when she saw the mug.  
"He’s here, isn’t he." It wasn’t a question.  
"Aren’t you going to… I don’t know. Put clothes on?" He blushed, trying to keep his eyes away from her naked body as she rose from the bed and grabbed the mug.  
Her response was getting even closer.  
"I’m _German_ , horseface. I’d get more embarrassed if I didn’t manage to get my computer working."  
He paused a moment to take the scene in. Her bedroom was a little messy, in very sober colors, she had those hipster christmas lamps on the wall above her bed, a magnetic paintjob on half the wall to his right, a galaxy projector on one nightstand, lots of books on some shelves, a pink laptop on the desk. In general, she had lots of girly stuff he had never dreamed possible for someone who punched that hard. He decided to look at the pics on the magnetic wall. Armin and Mikasa featured in a lot of those pics, he made the occasional photobomb (and he was surprised she even kept the pics on the SD card), and in more than a few pics, was a black haired guy with a bored look, but in some of those he appeared kissing her cheek and Eren was doing something he never thought she had the ability: blushing.  
"So. Levi, huh."  
He heard her choking on her coffee.  
" _Where did you hear that name?_ "  
"You talk in your sleep. Don’t get out of the subject."  
"There’s no subject, horseface. I don’t know what you’re talking about." He turned around to try and look her in the eye. He never knew she could blush, much less that her entire body blushed.  
"Ooooh, I think you do, lameass. You sleep with me, but you moan someone else’s name in your sleep and there’s this guy in your photowall I’ve never seen before, but he looks like he’s in college already. I’m not stupid."  
"Yes you are." She said defiantly. "I don’t see how who I fuck or don’t fuck is any of your business, Kirchstein."  
She was right on that point. Didn’t mean he was going to give up on getting his answer.  
"It’s not. I’m curious."  
"Well, stop being curious right now. I—" Her phone went off and Eren, in her carefulness not to drop coffee all over her bed and herself, didn’t make it to her phone in time to get it from Jean’s hands.  
"So you put three hearts before and after his name, Eren. I’m even more curious now, did you cheat on the guy with me, I’m flattered."  
He might have mentioned Eren is heavy-handed. He didn’t regret that question as much as he regretted the phrasing.  
"You can’t cheat when you’re not dating, idiot." She beat him into giving her phone back, unlocking it and reading the message, getting immediately agitated and dressed.  
"The fuck?"  
"Shit, shit, shit— the blue one or the red one?" He knew she was asking herself this but he couldn’t help but pipe in.  
"The red one makes your eyes kinda stand out."  
She turned around to face him with a raised eyebrow.  
"That sounded hella gay, Jean. Now get the fuck out, Levi’s coming over."  
"What’s got you so worked up about a guy coming over, man. You got a crush, don’t you?"  
The easiness with which he fell right back to their usual banter came with a wave of relief for him. He thought they would be awkward for a long long time before stopping talking to each other altogether.  
He got for that comment _exactly_ what he expected: a kick to the back of his knees.  
"He’s gonna show up any moment now, so can you kindly fuck off?"  
"Meh, I’ll stay, the scenery is nice even if it is you."  
A pillow made it’s way to his face followed by Eren’s fist. He noted she didn’t hit him half as hard as she normally did.  
A knock on her door put a quick end to whatever beating she was going to dish out.  
"Schatz, your boyfriend is here."  
She was still half naked, holding Jean by the hair, her fist up ready to beat him into a pulp, and suddenly she settled for a good old kick to the balls, leaving him to roll in agony while she slipped into stained dark wash denim short shorts and a long short sleeved red tshirt that covered it, before pulling up sheer black thigh highs and red converses.  
"Get the fuck out of my room, Jean, it’s almost midday, go home."  
"And miss out on seeing you head over heels for some college douchebag? No way."  
"Glad to know your friends think that high of me, Eren."  
They turned around to see the same black haired man from Eren’s pictures standing by the door, with the same uninterested look on his face.  
"Liked the shirt. Brings out your eyes." The Levi guy commented, and Eren blushed.  
"I feel like I’m interrupting something so I’m gonna just… Go."  
"Yeah, Jean, you do that." Eren said absentmindedly.  
As he skipped home, grabbing his shirt on the way out, he heard an outraged yell of ‘I did not!’, and ‘we’re not an item wasn’t that right?”  
He just hoped there wouldn’t be college-aged assassins in his bedroom to get him at night.

Eren’s POV OMAKE

As Jean closed the door, Levi narrowed his eyes.  
"So, cheating on me, right?"  
" _I DID NOT!_ " She yelled, outraged. ‘We’re not an item, wasn’t that right?"  
"Don’t shout, Eren." He made a face, rolling his eyes. "Didn’t think you would actually go through with your threat of sleeping with the first guy that struck your fancy."  
"I swear I wouldn’t do it, much less with Jean Horseface, but I was drunk and you were being an ass." She said, messing with the hem of her shirt, making it slip down her shoulder and expose her green bra strap.  
"Is… Is that a hickey on your shoulder?" She couldn’t not notice the way Levi’s eyes glinted with what she hoped was jealousy.  
"What if it is?"  
"Well…" He started, getting closer, and never before had she noticed she was slightly taller than him. "Gonna have to stick you into a bath, and get rid of him all over you and then leave some more permanent marks."  
Eren looked at him, wide-eyed, and actually thought he would throw her in the bathtub in her bathroom and do her there and then.  
"But I’m going to the mall first, I have house shopping to do. And I trust," he said, wrapping his arm around Eren’s waist, "that my sweet little girlfriend will help me find the right bed for my new apartment. After all, she’ll be sleeping there too."  
"… Are you talking about me?" Eren let herself be guided off, barely waving goodbye to her father.  
"And who else would I be talking about? Zoë? Wouldn’t get close to her with a 10-feet pole. Besides, she likes breaking dicks."  
Eren didn’t want to know how he knew that.

**Author's Note:**

> in case no one noticed, Eren's period synced with Jean and her's monthly fights. I wrote this while in a desperate attempt to sleep and that's my excuse to all the cracky lines. quick note: leiderhoser is a misspelling of lederhosen and it means 'unfortunately pants' and if you know what lederhosen is you will agree it is still a valid word for the thing. Schatz means 'treasure'.
> 
> Concrit is welcome! Pointing out mistakes and misspellings are also welcome, seeing as english is not my first language!


End file.
